Controller for a heater and an associated method of use

ABSTRACT

A controller for at least one heater, which includes a regulated voltage supply that is electrically connected to the at least one heater, at least one sensor operatively associated with at least one heater, at least one digital signal processor that is operatively connected to the at least one heater utilized in an injection molding system, the regulated voltage supply and the sensor operatively associated with the at least one heater based on feedback from the at least one sensor.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to control of a heater, and particularlyan improved controller utilizing a digital signal processor withfeedback for fast and accurate control of a heater that can be utilizedin an injection molding system.

BACKGROUND OF THE INVENTION

In a typical injection molding system, molten resin is loaded into atubular passage called a runner. The molten resin flows from the runnerthrough a gate valve and into the cavity of the mold. The resin in themold is then cooled and hardens into an article. The mold is opened andthe article is ejected.

In a cool runner injection molding system, resin inside the runner andthe cavity of the mold is cooled and ejected. In contrast, in a hotrunner injection system, resin in the hot runner is kept molten andinjected into the cavity during the next molding cycle. In order to keepthe resin in the runner molten, the runner is heated. In addition, theresin at the gate valve is cooled to prevent molten resin from drippingout when the mold is opened. This process requires precise and fasttemperature control to effectuate changes. In addition, in the hotrunner injection molding system, a heater can be utilized with a numberof components, including, but not limited to a barrel, a distributor,and a nozzle.

There are a number of different ways to heat the runner. These include:electric resistance heating; induction heating; and a combination ofboth types of heating. Induction heating consists of winding insulated,conductive wires around the area surrounding the runner near the gate.When the windings are supplied with high frequency power, the areaaround the runner is heated by electromagnetic induction.

U.S. Pat. No. 4,726,751 to Shibata et al. discloses a temperaturecontrol system for a hot runner plastic injection molding system wherethe voltage frequency is varied that is applied to the heater windings.However, Shibata et al. only adjusts the power to the heaters indiscrete, automatic steps with parallel resistors and/or capacitorsrather than utilizing seamless frequency variations based on a sensedtemperature. Furthermore, Shibata et al. is limited to only varyingvoltage frequency and not voltage amplitude. U.S. Pat. No. 4,726,751 toShibata et al. is incorporated herein by reference in its entirety.

U.S. Pat. No. 4,788,485 to Kawagishi et al., U.S. Pat. No. 5,136,494 toAkagi et al., U.S. Pat. No. 5,177,677 to Nakata et al., U.S. Pat. No.5,504,667 to Tanaka et al., and U.S. Pat. No. 5,663,627 to Ogawadisclose utilizing pulse width modulation to convert AC power to DCpower and are directed solely to motor control and not heating systems.U.S. Pat. No. 4,851,982 to Tanahashi discloses a system that uses pulsewidth modulation, conversion of AC power to DC power and then back to ACpower, and then varying the voltage and the frequency for use withelevator motors.

U.S. Pat. No. 5,285,029 to Araki, U.S. Pat. No. 4,545,464 to Nomura,U.S. Pat. No. 4,879,639 to Tsukahara, U.S. Pat. No. 4,894,763 to Ngo,U.S. Pat. No. 5,465,202 to Ibori et al., and U.S. Pat. No. 5,694,307 toMurugan disclose converting AC power to DC power and then back to ACpower but does not involve the field of temperature control. U.S. Pat.No. 6,603,672 to Deng discloses conversion of DC current to AC currentwhich is then converted from AC current to DC current and thencontrolling the output frequency. However, Deng does not discloseapplying these methods to temperature control in the field of heaters.U.S. Pat. No. 6,009,003 to Yeo and U.S. Pat. No. 4,816,985 to Tanahashidisclose current/voltage control for an elevator system.

U.S. Pat. No. 3,881,091 to Day discloses a control for heating currentsin a multiple cavity injection molding machine using a solid state,bidirectional conducting device for controlling current load, a phaseshifting capacitor connected to the conducting device, a variableresistor connected in parallel to the conducting device and a switch toshort out the variable resistor to maximize the flow of current.However, Day does not disclose utilizing a digital signal processor forcontrolling voltage frequency or amplitude. U.S. Pat. No. 3,881,091 toDay is incorporated herein by reference in its entirety.

U.S. Patent Application No. 2005/0184689 to Maslov et al. discloses amicroprocessor controller that alters the power supply based on currentfeedback. U.S. Pat. No. 6,090,318 to Bader et al. discloses taking amean of measured temperatures in individual hot runners and raising andlowering the measured melt temperatures together. This Reference alsoappears to teach away from the present invention by stating: “To preventcontinuous fluctuation in the hot-runner temperatures, however, the newtemperature set points for the various cavities are first compared withthe measured actual temperatures and the old set points, and only afterthis comparison in stage 33 of the computer is it decided whether acommand should be given to the hot-runner controller 17 to alter the setpoint for a cavity.” (Column 5, Lines 38-45). Therefore, there is not afast and efficient control of the heater but an analysis of a number ofset points and then an alteration of the current set point.

Existing temperature controllers are not capable of fast and precisecontrol of temperature. This lack of control allows temperature swingsin the heater windings which causes heater failure creating a majorproblem. As shown in FIG. 1, a large temperature excursion is shown inthe graph indicated by numeral 10. The temperature excursion (“dT”) is300° Celsius with duty cycle of 14 seconds on and 114 seconds off. Theresults for a first temperature sensor are indicated by numeral 76, theresults for a second temperature sensor are indicated by numeral 86 andthe results for a third temperature sensor are indicated by numeral 96.The heaters, measured by all three (3) temperature sensors 76, 86 and96, failed prior to 8,000 cycles. In addition, existing control systemsutilize either zero switching or phase firing for control of the voltagesupplied to the windings of the heaters. Phase firing introduces theproblem of electrical noise into the system which also makes itdifficult to have a fast and precise control of temperature.

The present invention is directed to overcoming one or more of theproblems set forth above.

SUMMARY OF INVENTION

In one aspect of this invention, a digital signal processor (“DSP”) thatcan utilize software algorithms, feedback signals, and output signals toprovide temperature control is disclosed. The DSP has the ability todigitally control temperature with both accuracy and speed.

In another aspect of this invention, a digital signal processor that canutilize both zero switching and phase firing control methods for controlof voltage for heating is disclosed. These control methods reduce heatertemperature oscillations around a set point in order to extend the lifeof a heater as well as reduce noise generation. Maximum voltage andfrequency will be applied to the windings of a heater for maximum heatgeneration without affecting the reliability of the heaters. The digitalsignal processor will use temperature feedback, set point control andmonitoring, and open loop percentage control that will give asignificant advantage in processing polymers with an injection moldingsystem where direct temperature control at the hot nozzle tip is notalways possible.

In still another aspect of this invention, a controller for at least oneheater is disclosed. The controller includes a regulated voltage supplythat is electrically connected to the at least one heater, at least onetemperature sensor located distal proximate to the at least one heater,and at least one digital signal processor that is operatively connectedto the at least one heater, the regulated voltage supply and the atleast one temperature sensor for regulating temperature of the at leastone heater based on feedback from the at least one temperature sensor, avoltage sensor, a current sensor or combination of sensors to achievebetter heater control.

In still another aspect of this invention, a controller for at least oneheater is disclosed. The controller includes a regulated voltage supplythat is electrically connected to the at least one heater, at least onefirst sensor associated with the at least one heater from the groupconsisting of a temperature sensor located distal proximate to the atleast one heater, a current sensor and a voltage sensor, at leastone.second sensor associated with at least one heater from the groupconsisting of a material state change sensor, a pressure sensor, aresistance shift sensor, a capacitance sensor, an inductance sensor, amaterial phase change sensor, a permeability sensor, a density sensor, aviscosity sensor, a shear feedback sensor, a material flow sensor, apolymerization response sensor, a strain sensor, a stress sensor and atransformation function sensor, and at least one digital signalprocessor that is operatively connected to the at least one heater, theregulated voltage supply, the at least one first sensor associated withthe at least one heater and the at least one second sensor associatedwith the at least one heater.

In still yet another aspect of the invention, a controller for at leastone heater is disclosed. The controller includes a regulated voltagesupply that is electrically connected to the at least one heater, atleast one first sensor from the group associated with the at least oneheater consisting of a temperature sensor located distal proximate tothe at least one heater, a current sensor and a voltage sensor, at leastone second sensor associated with the at least one heater from the groupconsisting of a material state change sensor, a pressure sensor, aresistance shift sensor, a capacitance sensor, an inductance sensor, amaterial phase change sensor, a permeability sensor, a density sensor, aviscosity sensor, a shear feedback sensor, a material flow sensor, apolymerization response sensor, a strain sensor, a stress sensor and atransformation function sensor, at least one digital signal processorthat is operatively connected to the at least one heater, the regulatedvoltage supply, the at least one first sensor and the at least onesecond sensor, at least one output switching module electricallyconnected to the at least one heater and the regulated voltage supply,wherein the at least one output switching module varies at least one ofvoltage and frequency to the at least one heater through at least one ofpulse width modulation and zero crossing detection, at least one triggercontrol module that transmits command signals to the output switchingmodule and the at least one trigger control module is electricallyconnected to the at least one digital signal processor and the regulatedvoltage supply, and at least one controller interface that iselectrically connected to the at least one digital signal processor.

In an aspect of the invention, a method for controlling temperature ofat least one heater is disclosed. The method includes receiving an inputvoltage with a regulated voltage supply that is electrically connectedto the at least one heater, obtaining at least one temperature valuefrom at least one temperature sensor located distal proximate to the atleast one heater, and regulating temperature of the at least one heaterwith at least one digital signal processor that is operatively connectedto the at least one heater, the regulated voltage supply and the atleast one temperature sensor.

In yet another aspect of the invention, a method for controllingtemperature of at least one heater is disclosed. The method includesreceiving an input voltage with a regulated voltage supply that iselectrically connected to the at least one heater, obtaining at leastone first input value from at least one first sensor associated with theat least one heater selected from the group consisting of a temperaturesensor located distal proximate to the at least one heater, a currentsensor and a voltage sensor, obtaining at least one second input valuefrom a second sensor associated with the at least one heater selectedfrom the group consisting of a material state change sensor, a pressuresensor, a resistance shift sensor, a capacitance sensor, an inductancesensor, a material phase change sensor, a permeability sensor, a densitysensor, a viscosity sensor, a shear feedback sensor, a material flowsensor, a polymerization response sensor, a strain sensor, a stresssensor and a transformation function sensor, and regulating the at leastone heater with at least one digital signal processor that isoperatively connected to the at least one heater, the regulated voltagesupply, the at least one first sensor and the at least one secondsensor.

These are merely some of the innumerable aspects of the presentinvention and should not be deemed an all-inclusive listing of theinnumerable aspects associated with the present invention. These andother aspects will become apparent to those skilled in the art in lightof the following disclosure and accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

For a better understanding of the present invention, reference may bemade to the accompanying drawings in which:

FIG. 1 illustrates a graphical representation of a large temperatureexcursion and associated effect on the life of a heater such as thatutilized in an injection molding system as found in the prior art;

FIG. 2 illustrates a schematic view of the temperature controlleraccording to the present invention; and

FIG. 3 illustrates a graphical representation of a small temperatureexcursion and associated effect on the life of a heater such as thatutilized in an injection molding system according to the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description, numerous specific details are setforth in order to provide a thorough understanding of the invention.However, it will be understood by those skilled in the art that thepresent invention may be practiced without these specific details. Inother instances, well-known methods, procedures, and components have notbeen described in detail so that the present invention will not beobscured.

FIG. 2 illustrates a schematic view of a temperature controlleraccording to the present invention that is generally indicated bynumeral 5. In the present invention, the temperature controller 5utilizes a digital signal processor (“DSP”) 50, which is preferably butnot necessarily embedded. The digital signal processor (“DSP”) 50handles all of the software programs, feedback signals, and outputsignals that are utilized in the control of what is preferably, but notnecessarily, an injection molding system. The present invention acceptsa wide range of supply voltages 18, e.g., 110 Volts AC to about 600Volts AC, at any frequency, e.g., 50 Hz to about 400 Hz and with one tothree phases.

The supply voltage 18 is then converted to a DC voltage by a voltagerectifier and regulator module 20. The voltage rectifier and regulatormodule 20 is electrically connected to a voltage filtering and feedbackstage 30 to ensure the quality of the DC voltage supply to the heaters74, 84 and 94, respectively, that may be utilized with injection moldingequipment 75, 85 and 95, respectively.

Preferably, but not necessarily, the voltage rectifier and regulatormodule 20 includes a series of thyristors 22 and at least one diode 24.Also, triacs, transistors, and other comparable types of electricalcomponents can be utilized for the voltage rectification and regulationin the regulator module 20. Preferably, but not necessarily, the voltagerectifier and regulator module 20 can provide phase angle control, timeproportioning and true power control. True power control can compensatefor physical property changes in the heaters 74, 84 and 94 and/orvoltage changes.

The voltage filtering and feedback stage 30 preferably, but notnecessarily includes at least one inductor 32 and at least one capacitor34. The rectified, regulated, and filtered voltage is then provided tothe heaters 74, 84 and 94, respectively, utilized preferably, but notnecessarily with the injection molding equipment 75, 85 and 95,respectively in one aspect of this invention where DC voltage is usedfor accurate set point maintenance. Understandably, the voltagefiltering and feedback stage 30 will generate pulses of variable timebase and variable amplitude proportionate with sensory feedback andcommunicate this to an output device, which in this illustrative, butnonlimiting, example is a heater. The rectified, regulated, and filteredvoltage is also measured 36 with this measured voltage being fed back tothe digital signal processor 50.

Moreover, the present invention is also optionally capable of generatingcontrol signals for controlling various injection molding systems andcomponents 75, 85 and 95, including water, mold base heating/cooling,cavity pressure and hydraulically operated material flow modulators inaddition to mold temperature.

The digital signal processor 50 employs software control algorithms togenerate control signals. Modifications, updates and new controlfeatures can be done in software thereby reducing cost compared tocontrols utilizing programmable controllers and/or analogmicroprocessors. The digital signal processor 50 is capable of automatictuning by calculating optimum PID (“Proportional-Integral-Derivative”)and other parameters required by the control scheme, e.g., feed-forward,PID control algorithm, slope control, differential inputs and otherknown methods. The most common control methodology is in processcontrol. Preferably, this is a continuous feedback loop that keeps theprocess flowing normally by taking corrective action whenever there isany deviation from the desired value (“set point”) of the processvariable (rate of flow, temperature, voltage, etc.). An “error” occurswhen an operator manually changes the set point or when an event (valveopened, closed, etc.) or a disturbance changes the load, thus causing achange in the process variable. The PID(“Proportional-Integral-Derivative”) controller receives signals fromsensors and computes corrective action to the actuators from acomputation based on the error (proportional), the sum of all previouserrors (integral) and the rate of change of the error (derivative).

The automatic calculation of PID parameters is accomplished by switchingthe output on and off to induce oscillations in the measured value. Fromthe amplitude and the period oscillation, the PID parameters arecalculated. This auto tuning is performed whenever the thermal loadchanges.

The present invention preferably includes a controller interface 60 thatinterprets operator input and generates commands to the digital signalprocessor 50. The digital signal processor 50 is configured with thecontroller interface 60 to run the process. There could also be supportfor a portable processor, e.g., laptop, visualizations in addition to astandalone operation (not shown). The controller interface 60 can beset-up to provide user access levels with different associated rightsfor each particular category of user.

The controller interface 60 may also include a menu structure such thatsetup, operation, debugging, and data collection are grouped together ina logical manner. The controller interface 60 may contain clear visualcues to injection molding system conditions and actions. The input froma user is preferably minimized to run the controller interface 60 andrespond to alarm conditions.

The present invention may include a digital communications module 65that is capable of communicating with a wide variety of computernetworks, e.g., WAN, LAN, global computer network, e.g., the Internet,and so forth. A wide variety of output devices such as printers (notshown) can be electrically connected to the digital communicationsmodule 65.

This would allow for remote access and troubleshooting. The digitalcommunications module 65 could also include a Serial PeripheralInterface (“SPI”) port, which is a full-duplex synchronous serialinterface for connecting low/medium bandwidth external devices usingfour wires. Serial Peripheral Interface (“SPI”) port communicates usinga master/slave relationship over two data lines and two control lines.The digital communications module 65 may also include an RS232 port,among other types of digital communication. In addition, the digitalcommunications module 65 could be configured for local intra-modulecommunication, e.g., Profibus, Ethernet, radio frequency (“RF”) linkover a power wire, and so forth.

In another embodiment of the invention, the digital communicationsmodule 65 is electrically connected to a wireless interface device 62.This wireless interface device 62 provides electronic communication witha wide variety of wireless devices 67 including, but not limited to, ahand-held unit; a radio frequency (“RF”) controlled unit; a wirelesslocal area network (“LAN”) connected unit; a personal digital assistant(“PDA”), among other types of portable digital, wireless devices.

Another aspect of the present invention is that the temperaturecontroller 5 is utilized to control the temperature of the heaters 74,84 and 94, that are typically in the form of resistive heaters,inductive heaters, or heaters that are a combination of both resistiveheaters and inductive heaters.

The digital signal processor 50 handles all of the software programs andclosed loop controls for temperature in addition to generating commandsignals to the trigger control module 40 for control of the voltagerectifier and regulator module 20 and the output switching stages 70,80, and 90.

The output switching stages 70, 80, and 90 are responsible for producingvariable frequency to each heater 74, 84 and 94 with voltage (power)pulses modulated by switching devices, e.g., IGBTs, MOSFETs, that allowfor DC current to be applied to each of the heaters 74, 84 and 94 whenthe software program determines heater set point stability and long lifeare needed. Preferably, but not necessarily, the output from each of theoutput switching stages 70, 80, and 90 is a voltage with a frequency ofup to 400 Hz at about 240 Volts AC. Moreover, in the alternative, theoutput switching stages 70, 80, and 90 could be configured to provide afrequency in the range of from about 0 Hz to about 200,000 Hz.

The digital signal processor 50 employs a PID temperature controlalgorithm that is configured to control the temperature of the heaterwindings with a high degree of accuracy, e.g., +/−0.1° Celsius, in awide temperature range, e.g., 0° Celsius through about 8000 Celsius.This software platform is expandable to support multiple PID controlloops for system voltage, current, and frequency. Voltage is controlledusing zero crossing and phase control and preferably the PID controlloop is applied to voltage amplitude control in a way that output fromthe heaters 74, 84 and 94 is proportional to device supplied voltage. Inaddition to control functions, the digital signal processor 50 is alsoconfigured to detect open circuits, reverse wires, pinched wires, andshort circuit conditions in the feedback sensing circuits 36, 92, 96, aswell as in power circuit 74, 84 and 94. Furthermore, the digital signalprocessor 50 may detect when one of the heaters 74, 84, and 94 may bewet and apply an appropriate voltage to dry the heaters 74, 84, and 94,i.e., a bake-out function, utilizing moisture detection and moisturemitigation algorithms. Furthermore, the digital signal processor 50 maydetect incorrect wiring connections to any output devices 74, 84, 94.

In order for the digital signal processor 50 to implement controlfunctions, the digital signal processor 50 is configured to acceptvarious system measurements, e.g., injection molding systemmeasurements. Preferentially, output signals are created by the digitalsignal processor 50 based on sensory input from sensors (“sensors”) 102,104 and 106. Sensors 102, 104 and 106 may include, but are not limitedto: a material state change sensor; a pressure sensor; a resistanceshift sensor; a capacitance sensor; an inductance sensor; a materialphase change sensor; a permeability sensor; a density sensor; aviscosity sensor; a shear feedback sensor; a material flow sensor; apolymerization response sensor; a strain sensor; a stress sensor; and atransformation function sensor.

An illustrative, but nonlimiting, example of a sensor for monitoring amaterial state change sensor includes, but is not limited to, a fiberoptic raman spectrometry (FORS) sensor that provides real time materialstate information. An illustrative, but nonlimiting, example of a sensorfor monitoring pressure includes, but is not limited to, a transducer.An illustrative, but nonlimiting, example of a sensor for monitoringresistance shift includes, but is not limited to, a quartz crystal. Anillustrative, but nonlimiting, example of a sensor for monitoringcapacitance of a circuit includes, but is not limited to, acapacitance-to-digital conversion integrated circuit. An illustrative,but nonlimiting, example of a sensor for monitoring inductance of acircuit includes, but is not limited to, an inductance-to-digitalconversion integrated circuit.

An illustrative, but nonlimiting, example of a sensor for monitoringmaterial phase change includes, but is not limited to, a sensor thatutilizes a hydrogel. An illustrative, but nonlimiting, example of asensor for monitoring permeability includes, but is not limited to, apermeability sensor. An illustrative, but nonlimiting, example of asensor for monitoring viscosity includes, but is not limited to, aviscosity sensor utilizing a cylinder and piston. An illustrative, butnonlimiting example of a sensor for monitoring shear feedback includes,but is not limited to, an integrated tactile/shear feedback array.

An illustrative, but nonlimiting, example of a sensor for monitoringmaterial flow includes, but is not limited to, a sensor responsive to amaterial flow rate. An illustrative, but nonlimiting, example of asensor for monitoring polymerization response includes, but is notlimited to, a polymerization response sensor. An illustrative, butnonlimiting, example of a sensor for monitoring strain and/or stressincludes, but is not limited to, a piezo-electric sensor element. Anillustrative, but nonlimiting, example of a sensor for monitoring atransformation function includes, but is not limited to, a sensor whoseoutput is modified via a transformation function.

A universal input with an advanced analog to digital converter can beutilized to sample the inputs during predetermined time intervals, e.g.,10 milliseconds or better at 120 Hz, and continuously to correct fordrift. High noise immunity is achieved by rejection of pickup, e.g.,50/60 Hz, and other sources of noise. The resistance (impedance) of theheaters 74, 84 and 94 is measured to determine when one of the heaters74, 84 and 94 might fail in order to perform scheduled maintenance. Thetemperature of the heaters 74, 84 and 94 is measured with sensors 76,86, and 96 and these measured values are then provided to the digitalsignal processor 50.

Illustrative, but nonlimiting, examples of temperature sensors include,but are not limited to, a thermocouple, a resistance temperaturedetector (“RTD”), and a pyrometer.

Moreover, the current to the heaters 74, 84 and 94 is also measured withsensors 72, 82 and 92 and these measured values are also provided to thedigital signal processor 50. The current is controlled with set pointcontrol and then open loop percentage control to control temperaturearound the set point. Leakage current is measured to identify a wetheater condition for at least one of the heaters 74, 84 and 94 todetermine when to activate the bake-out function and apply suitablymodulated output.

The result of utilizing the present invention with a small temperatureexcursion (“dT”) of 30° Celsius, with 2 seconds on and 8 seconds off sothat all heaters 74, 84 and 94 can cycle past 10,000 cycles as shown inFIG. 3. The results for a first temperature sensor are indicated bynumeral 76, the results for a second temperature sensor are indicated bynumeral 86 and the results for a third temperature sensor are indicatedby numeral 96. As shown, this will provide a tremendous increase inreliability.

Thus, there has been shown and described several embodiments of a novelinvention. As is evident from the foregoing description, certain aspectsof the present invention are not limited by the particular details ofthe examples illustrated herein, and it is therefore contemplated thatother modifications and applications, or equivalents thereof, will occurto those skilled in the art. The terms “have,” “having,” “includes” and“including” and similar terms as used in the foregoing specification areused in the sense of “optional” or “may include” and not as “required.”Many changes, modifications, variations and other uses and applicationsof the present construction will, however, become apparent to thoseskilled in the art after considering the specification and theaccompanying drawings. All such changes, modifications, variations andother uses and applications which do not depart from the spirit andscope of the invention are deemed to be covered by the invention whichis limited only by the claims that follow.

1. A controller for at least one heater comprising: a regulated voltagesupply that is electrically connected to the at least one heater; atleast one temperature sensor located distal proximate to the at leastone heater; and at least one digital signal processor that isoperatively connected to the at least one heater, the regulated voltagesupply and the at least one temperature sensor for regulatingtemperature of the at least one heater based on feedback from the atleast one temperature sensor.
 2. The controller for at least one heateraccording to claim 1, further comprising at least one output switchingmodule electrically connected to the at least one heater and theregulated voltage supply, wherein the at least one output switchingmodule varies at least one of voltage and frequency to the at least oneheater through at least one of pulse width modulation and zero crossingdetection.
 3. The controller for at least one heater according to claim2, further comprising at least one trigger control module that transmitscommand signals to the output switching module, wherein the at least onetrigger control module is electrically connected-to the at least onedigital signal processor and the regulated voltage supply.
 4. Thecontroller for at least one heater according to claim 1, furthercomprising at least one controller interface that is electricallyconnected to the at least one digital signal processor.
 5. Thecontroller for at least one heater according to claim 1, furthercomprising at least one current sensor that is electrically connected tothe at least one digital signal processor.
 6. The controller for atleast one heater according to claim 1, further comprising at least onevoltage sensor that is electrically connected to the at least onedigital signal processor.
 7. The controller for at least one heateraccording to claim 1, further comprising a sensor, which is electricallyconnected to the at least one digital signal processor, to provideinput, wherein the sensor selected from the group consisting of amaterial state change sensor, a pressure sensor, a resistance shiftsensor, a capacitance sensor, an inductance sensor, a material phasechange sensor, a permeability sensor, a density sensor, a viscositysensor, a shear feedback sensor, a material flow sensor, apolymerization response sensor, a strain sensor, a stress sensor, and atransformation function sensor.
 8. The controller for at least oneheater according to claim 1, wherein the regulated voltage supply iscapable of receiving alternating current voltage in a range from about110 Volts to about 600 Volts in a frequency range from about 50 Hz toabout 400 Hz in at least one phase.
 9. The controller for at least oneheater according to claim 1, wherein the at least one digital signalprocessor utilizes zero crossing time proportioning control and phasefired voltage control.
 10. The controller for at least one heateraccording to claim 1, wherein the at least one digital signal processorutilizes control features selected from the group consisting ofautomatic tuning, PID feedback loop, feed forward, slope control, or cutback.
 11. The controller for at least one heater according to claim 1,further including a voltage filtering stage that is electricallyconnected to the regulated voltage supply to smooth rectified voltagecoming from the regulated voltage supply.
 12. The controller for atleast one heater according to claim 4, wherein the at least onecontroller interface further includes an electronic display.
 13. Thecontroller for at least one heater according to claim 1, furthercomprising a digital communications module that is connected to acomputer network.
 14. The controller for at least one heater accordingto claim 13, wherein the computer network includes a global computernetwork.
 15. The controller for at least one heater according to claim13, further comprising a wireless interface device that is in electroniccommunication with the digital communications module.
 16. The controllerfor at least one heater according to claim 15, wherein the wirelessinterface can communicate with a wireless device selected from the groupconsisting of a hand-held unit, a radio frequency controlled unit, apersonal digital assistant, a portable processor or a radio frequencylink over power wire communication.
 17. A controller for at least oneheater comprising: a regulated voltage supply that is electricallyconnected to the at least one heater; at least one first sensorassociated with the at least one heater from the group consisting of atemperature sensor located distal proximate to the at least one heater,a current sensor and a voltage sensor; at least one second sensorassociated with at least one heater from the group consisting of amaterial state change sensor, a pressure sensor, a resistance shiftsensor, a capacitance sensor, an inductance sensor, a material phasechange sensor, a permeability sensor, a density sensor, a viscositysensor, a shear feedback sensor, a material flow sensor, apolymerization response sensor, a strain sensor, a stress sensor and atransformation function sensor; and at least one digital signalprocessor that is operatively connected to the at least one heater, theregulated voltage supply, the at least one first sensor associated withthe at least one heater and the at least one second sensor associatedwith the at least one heater.
 18. The controller for at least one heateraccording to claim 17, further comprising at least one output switchingmodule electrically connected to the at least one heater and theregulated voltage supply, wherein the at least one output switchingmodule varies at least one of voltage and frequency to the at least oneheater through at least one of pulse width modulation and zero crossingdetection.
 19. The controller for at least one heater according to claim18, further comprising at least one trigger control module thattransmits command signals to the output switching module, wherein the atleast one trigger control module is electrically connected to the atleast one digital signal processor and the regulated voltage supply. 20.The controller for at least one heater according to claim 17, furthercomprising at least one controller interface that is electricallyconnected to the at least one digital signal processor.
 21. Thecontroller for at least one heater according to claim 20, wherein the atleast one controller interface further includes an electronic display.22. The controller for at least one heater according to claim 17,further comprising a digital communications module that is connected toa computer network.
 23. The controller for at least one heater accordingto claim 22, further comprising a wireless interface device that is inelectronic communication with the digital communications module.
 24. Acontroller for at least one heater comprising: a regulated voltagesupply that is electrically connected to the at least one heater; atleast one first sensor associated with the at least one heater from thegroup consisting of a temperature sensor located distal proximate to theat least one heater, a current sensor and a voltage sensor; at least onesecond sensor associated with at least one heater from the groupconsisting of a material state change sensor, a pressure sensor, aresistance shift sensor, a capacitance sensor, an inductance sensor, amaterial phase change sensor, a permeability sensor, a density sensor, aviscosity sensor, a shear feedback sensor, a material flow sensor, apolymerization response sensor, a strain sensor, a stress sensor and atransformation function sensor; at least one digital signal processorthat is operatively connected to the at least one heater, the regulatedvoltage supply, the at least one first sensor associated with at leastone heater and the at least one second sensor associated with at leastone heater; at least one output switching module electrically connectedto the at least one heater and the regulated voltage supply, wherein theat least one output switching module varies at least one of voltage andfrequency to the at least one heater through at least one of pulse widthmodulation and zero crossing detection; at least one trigger controlmodule that transmits command signals to the output switching module andthe at least one trigger control module is electrically connected to theat least one digital signal processor and the regulated voltage supply;and at least one controller interface that is electrically connected tothe at least one digital signal processor.
 25. A method for controllingtemperature of at least one heater comprising: receiving an inputvoltage with a regulated voltage supply that is electrically connectedto the at least one heater; obtaining at least one temperature valuefrom at least one temperature sensor located distal proximate to the atleast one heater; and regulating temperature of the at least one heaterwith at least one digital signal processor that is operatively connectedto the at least one heater, the regulated voltage supply and the atleast one temperature sensor.
 26. The method for controlling temperatureof at least one heater according to claim 25, further comprising varyingat least one of voltage and frequency to the at least one heater throughat least one of pulse width modulation and zero crossing detection withat least one output switching module that is electrically connected tothe at least one heater and the regulated voltage supply.
 27. The methodfor controlling temperature of at least one heater according to claim25, further comprising transmitting command signals to the outputswitching module, wherein the at least one trigger control module iselectrically connected to the at least one digital signal processor andthe regulated voltage supply.
 28. The method for controlling temperatureof at least one heater according to claim 25, further comprisingproviding user input and receiving output with at least one controllerinterface that is electrically connected to the at least one digitalsignal processor.
 29. The method for controlling temperature of at leastone heater according to claim 25, further comprising receiving inputfrom at least one of a current sensor and a voltage sensor that iselectrically connected to the at least one digital signal processor. 30.The method for controlling temperature of at least one heater accordingto claim 25, further comprising utilizing zero crossing timeproportioning control and phase fired voltage control with the at leastone digital signal processor.
 31. The method for controlling temperatureof at least one heater according to claim 25, further comprisingutilizing at least one of a digital communications module and a wirelessinterface.
 32. The method for controlling temperature of at least oneheater according to claim 31, wherein the digital communications moduleis operatively connected to a global computer network.
 33. The methodfor controlling temperature of at least one heater according to claim31, wherein the wireless interface can communicate with a wirelessdevice selected from the group consisting of a hand-held unit, a radiofrequency controlled unit, a personal digital assistant, a portableprocessor or a radio frequency link over power wire communication.
 34. Amethod for controlling temperature of at least one heater comprising:receiving an input voltage with a regulated voltage supply that iselectrically connected to the at least one heater; obtaining at leastone first input value from a first sensor associated with the at leastone heater selected from the group consisting of a temperature sensorlocated distal proximate to the at least one heater, a current sensorand a voltage sensor; obtaining at least one second input value from asecond sensor associated with the at least one heater selected from thegroup consisting of a material state change sensor, a pressure sensor, aresistance shift sensor, a capacitance sensor, an inductance sensor, amaterial phase change sensor, a permeability sensor, a density sensor, aviscosity sensor, a shear feedback sensor, a material flow sensor, apolymerization response sensor, a strain sensor, a stress sensor and atransformation function sensor; and regulating the at least one heaterwith at least one digital signal processor that is operatively connectedto the at least one heater, the regulated voltage supply, the at leastone first sensor and the at least one second sensor.
 35. The method forcontrolling temperature of at least one heater according to claim 34,further comprising varying at least one of voltage and frequency to theat least one heater through at least one of pulse width modulation andzero crossing detection with at least one output switching module thatis electrically connected to the at least one heater and the regulatedvoltage supply.
 36. The method for controlling temperature of at leastone heater according to claim 34, further comprising transmittingcommand signals to the output switching module, wherein the at least onetrigger control module is electrically connected to the at least onedigital signal processor and the regulated voltage supply.
 37. Themethod for controlling temperature of at least one heater according toclaim 34, further comprising providing user input and receiving outputwith at least one controller interface that is electrically connected tothe at least one digital signal processor.
 38. The method forcontrolling temperature of at least one heater according to claim 34,further comprising utilizing at least one of a digital communicationsmodule and a wireless interface, wherein the wireless interface cancommunicate with a wireless device selected from the group consisting ofa hand-held unit, a radio frequency controlled unit, a personal digitalassistant, a portable processor or a radio frequency link over powerwire communication.